Fraud detector



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73$? Jan. 4, 1938. J. s. KAHN 2,104,079 5 7 FRAUD DETECTOR v Filed Sept.29, 1934 INVENTOR.

JULIAN S. KAHN ATTORNEYS Patented Jan. 4, 1938 UNITED STATES uucll ulnuum PATENT OFFICE FRAUD DETECTOR Julian Seth Km, New York, N. Y.

Application September 29, 1934, Serial No. 746,058

2 Claims.

This invention relates to new and useful improvements in frauddetectors, and is particularly useful for detecting forgeries in checks,wills, etc.

I have discovered that chemicals which are invisible in ordinary lightbecome visible when viewed in light of particular wave lengths, and thatvarious other substances when viewed in light of the same wave lengthstake on a dif 10 ferent aspect than when viewed in ordinary light.

This is particularly noticeable in the casev of chemicals which are usedas ink removers. The signature of a check, or the amount of money forwhich the check is written, may be completely removed by a suitable inkeradicator, and a difi'erent amount of money or signature inserted. Inordinary light the altered check may appear to be perfectly regular. Ifviewed in light of the wave lengths utilized in practising my inventionthe original writing stands out with perfect clarity so that it is notonly immediately obvious that the check has been changed, but theoriginal writing on the check may be observed.

My invention also finds use in the case of forged bills. A bill whichhas been engraved with ink other than that used by the United StatesGovernment may appear in ordinary light to be perfectly genuine. If itis compared with a genuine bill under the light I use with my invention,the difference in the inks becomes immediin. A genuine gem may becompared with an imitation and the imitation at once detected,

while fiaws in a gem stand out in a much more pronounced manner than inordinary light.

After a large number of experiments with various wave lengths of light Ihave discovered that the best results are obtained when all wave lengthsare absorbed by my light I filter except those wave lengths in thevisible portion of the spectrum lying approximately between 6745 and7580 Angstrom units and that portion in the violet between approximately3407 and 4132 Angstrom units. Small quantities of light of other wavelengths may be present without seriously affecting the results, and thewave lengths mentioned may vary by as much as 100 Angstrom units andstill be useful.

In order to produce light of these wave lengths I use an incandescentbulb with a tungsten filament, such as those produced commercially forhousehold use. For best results the temperature of the filament shouldbe approximately 3000 degrees centigrade. This temperature may beobtained by using a watt, 64 volt light on a volt line. I may alsoobtain results which are reasonably satisfactory, but not of the best,with a lamp in which the filament is at a lower temperature such as maybe obtained for example by using a 250 watt 110 volt lamp on a 110 voltline.

In combination with the light source I provide a light filter. The lightfilter with which I have had the best results is a fiece of opticalnickelcobalt glass such as may be obtained from any glass manufacturer.In fact the Coming Glass Works of Coming, New York, produce a glasswhich they call their No. 587, which produces excellent results.Although this particular glass transmits a small quantity ofultrae-violet light along with the wave lengths mentioned above, I havediscovered in the course of my experiments that this ultra violet lightdoes not in any way enhance the results.

For the best results in practising my invention the light should beconcentrated on the object to be viewed and other light should be shutoff, that is the room should be darkened, but this is not absolutelynecessary as if the light is sufficiently concentrated the results maybe observed in a room to which a normal amount of daylight is beingadmitted.

In practising my invention I assemble the apparatus in suitable compactform, as shown in the drawing, in which Fig. 1 is a perspective view ofmy apparatus; and

Fig. 2 is a section along the line 2-2 of Fig. 1.

In the drawing there is a casing 3 in which is enclosed an electriclight bulb 4, as above described. Wires 5 lead into the casing and tothe bulb. The electricity may be turned on or off by means of a switch 6mounted on the casing. I provide vent holes 1 in the casing to affordsuitable ventilation in order to avoid overheating. The inner surface ofthe casing is provided with an aperture in which is held a piece ofoptical nickel-cobalt glass 8. A sliding retaining member 9 is providedto hold the glass in place so that in the event it should become brokenit may be easily replaced. Two sections l0 and II are provided to slidein apertures at two opposite edges of the inner surface of the casing 3.To these members are hinged triangular sections l2 and I3 having notchesI 4 at one comer. Also secured to these members l0 and II by means ofnuts 2|, 22, are sliding base members I5 and I6.

My apparatus is shown open and arranged for use in Fig. l. The object tobe examined is placed on the base members l5, l6 under the light frombulb 4 coming through filter 8. In order to close it so that it may becarried from place to place, if desired, the notches H are removed fromthe comers of the base members l5 and I 6 and the wings I2 and I3 foldedinwardly. This releases the base members l5 and I6 which may then befolded upward and the entire sections l0, l2 and IS on one side and H,l3 and IE on the other pushed towards one another so that the apparatusis folded into a compact box. A brace I! gives added strength to thestructure.

The apparatus may be used directly over a bulky object, such as aledger, by removing nuts 2| and 22, which permits the removal of basemembers l6 and I6.

What is claimed is:

1. A fraud detector comprising a casing, an electric light bulb enclosedwithin said casing, a window in said casing, a piece of opticalnickelcobalt glass in said window, a pair of wing members slidablymounted in said casing, and a pair of base members secured to said wingmembers and adapted to be opened to form a surface partially enclosed bysaid wing members on which an object may be placed for inspection.

2. The combination in accordance with claim 1 comprising means fordetaching said base members.

JULIAN SETH KAI-IN.

